The invention concerns an apparatus for fixing fasteners by means of combustion of an inflammable compressed gas, used in particular in the building industry to fasten to a support mounting plate for the fixing of cables, ducts and other accessories of this type.
This type of fixing apparatus comprises a cylinder, into which is slide mounted a fastener propelling piston, a combustion chamber, a housing to receive a compressed gas cartridge, a removable magazine for the supply of fasteners, a fastener-guide, a shearing unit and a handle.
The fastener supply magazine, removable, contains a strip of fastener-holding rings. The shearing unit comprises a passage to accept fasteners which connects with the fastener magazine and extends forwards via a fastener guide passage of the fastener-guide, for the purpose of guiding the fastener until it penetrates the support.
At time of firing, the fastener at the head of the support strip is inserted into the shearing unit and, after the apparatus is pressed against a support, the piston is propelled forwards and strikes the fastener which has been accepted into the shearing unit. As a result of the strike, the strip of fastener-holding rings is sheared, the fastener at the head of the strip, detached, is projected forwards, guided by the fastener-guide, and penetrates the support.
The shearing unit of known devices consists of two parts, upper and lower, each having formed in it a groove semicircular in cross-section. The upper part is integral with the fastener-guide and with a casing enclosing the cylinder and the combustion chamber, and the lower part is integral with the fastener supply magazine. When the fastener supply magazine is mounted on the apparatus, the lower part and the upper part are indexed in relation to each other and firmly united by means of two pins projecting from the lower part and received into two transverse openings formed in the upper part. After the two parts, upper and lower, are firmly joined, the two semicircular grooves form the fastener reception passage. The fastener supply magazine and the shearing unit are then locked, by means of a locking system with a knob, in order to prevent the separation of the upper and lower parts.
When the fastener magazine is withdrawn from the apparatus, the lower part of the shearing unit is likewise removed. For safety reasons, a system, usually electronic, prevents the firing of the apparatus without the fastener magazine.
The operation consisting of indexing the two parts of the shearing unit and then locking the latter is tedious. In addition, with the fixing apparatus described above, it is impossible to fire without the fastener supply magazine. However, it would be of interest to be able to use the apparatus without its fastener magazine, for example for fixing a premounted fastener onto a part to be fixed.
The present invention aims to overcome the above disadvantages.
To this end, the invention concerns a fastener fixing apparatus comprising a removable magazine for supplying fasteners, designed to contain a strip of fastener-holding rings, a fastener-guide and a unit for shearing the strip of fastener-holding rings, characterised by the fact that the shearing unit is functionally a single unit.
With the fixing apparatus of the invention, after removal of the apparatus""s fastener magazine, the shearing unit remains intact. The apparatus can therefore be used with or without the fastener magazine. As a result, the safety system preventing firing after removal of the fastener magazine is eliminated. Furthermore, the apparatus, without the fastener magazine, can, be used to fix a fastener in a deep section, which would be impossible with the fastener magazine mounted onto the apparatus because of the magazine""s bulk.
To advantage, the shearing unit and the fastener supply magazine are adapted to work together by housing a skirt, to form a fastener input passage, in a compartment for receiving the skirt.
It is thus possible to index the magazine in relation to the apparatus without difficulty.
For preference, the skirt and its housing compartment are modelled so that the one fits into the other loosely.
As a result, the fastener magazine can be very easily mounted onto the apparatus.
For preference again, the skirt is integral with the shearing unit.
For further advantage, the design is such that the fastener supply magazine fixes onto the apparatus by means of a snap fit.